Field of the Invention
The present invention relates to a Group III nitride semiconductor light-emitting device and a production method therefor, more specifically, to a method for producing a Group III nitride semiconductor light-emitting device having pits.
Background Art
A Group III nitride semiconductor light-emitting device comprises a light-emitting layer which emits light through recombination of electrons and holes, an n-type semiconductor layer, and a p-type semiconductor layer. When producing the Group III nitride semiconductor light-emitting device, a semiconductor layer is epitaxially grown on a substrate. In this case, threading dislocation occurs in the semiconductor layer due to lattice mismatch between the substrate and the semiconductor layer. In the threading dislocation, non-light-emitting recombination of electrons and holes occurs. Non-light-emitting recombination refers to a recombination of electrons and holes which generates not light but heat. Therefore, electrons existing in the vicinity of the threading dislocation may cause non-light-emitting recombination at the threading dislocation. The more frequently non-light-emitting recombination occurs, the more heat the semiconductor light-emitting device generates. The emission efficiency of the semiconductor light-emitting device is decreased by the amount of the generated heat.
Therefore, the technique has been developed to suppress non-light-emitting recombination in the threading dislocation. For example, Patent document 1 discloses the technique to generate pits due to threading dislocation on the n-type GaN layer (refer to paragraphs [0014] to [0016] of Patent Document 1). In the technique, pits are filled with an AlGaN barrier layer. Therefore, the AlGaN barrier layer serves as a barrier so that electrons and holes are hardly reach the threading dislocation (refer to paragraph of Patent Document 1). As a result, the semiconductor light-emitting device exhibits high emission efficiency.
Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. 2002-368269
In this way, the emission efficiency of the semiconductor light-emitting device has been improved through research and development. However, to improve the emission efficiency, it is required that electrons and holes are not further captured by threading dislocation.